Device for controlling the position of a sheet receiving table



June 20, 1967 E TREFF 3,326,549

DEVICE FOR CONTROLLING THE POSITION OF A SHEET RECEIVING TABLE Filed July 6, 1965 ATTORNEYS United States Patent DEVICE FOR CONTROLLING THE POSITION OF A SHEET RECEIVING TABLE Ernest H. Treff, Port Washington, N.Y., assignor to F. L.

Smithe Machine Co., Inc., New York, N.Y., a corporation of New York Filed July 6, 1965, Ser. No. 469,404 2 Claims. (Cl. 271-88) This invention relates to devices which deliver sheets of paper or the like as, for instance, from a printing press in a pile for use in a further machine.

-It is an essential requirement, or at least a very desirable one, that such a machine deliver the complete material in the form of a stack which is accurately piled, that is, a stack which does not require jogging or squaring up before-the stack is placed in a further machine. At slow speeds such a delivery requires no particularly elaborate equipment, but at extremely high speeds considerable difiiculties may be experienced in getting each sheet to take its proper position in the pile as it is fed from the machine. In US. Patent 3,141,667, there is shown on solution to this problem. In that patent, at FIG. 10, there is shown a delivery wheel 32 which by means of suction mechanism grasps each blank or piece of material coming from the conveyor, and carries it into position on a table at which point it releases the object. Because of the nature of the device it is essential that each of the elements 16 be delivered to the top of the pile with the top surface at a more or less closely controlled position relative to the wheel 32. In the patent this is accomplished by means of achain 214 which is driven by means of an indexing mechanism 216 at a speed which is intended to keep the top surface of the pile of delivered sheets in a constant spatial relationship to the wheel 32. This is done by simply moving a platform downwardly at a rate which is meant to exactly equal the rate of growth of the pile of the sheets. It has been found from experience that the height of the pile of sheets is not predictable with a sulficient degree of accuracy to permit the use of the mechanism shown in FIG. 10 without considerable hand control of the speed of the stacker indexing mechanism. This is because the material, which is normally paper, behaves in an-unpredictable-manner even though a stack of the same paper seems to be coming from the machine as was fed in a previous one. This is due in some part to the curl in the paper which may vary according to the temperatures or humidity or previous storage conditions of the paper coming from the machine, and there is also variation in the amount of air which may be trapped between the sheets as they are fed to the table. There are a number of other variables such as for example the tendency of certain types of paper to settle as the load on the top is increased which makes the achievement of a table type control dependent upon the counting of the fed sheets, which is practically a hopeless task without supervision by the operator. Such supervision is thus required in machines of this type in order to produce a stack of delivered sheets which does not require jogging or squaring up. It is possible with low speed machines to provide a device which presses down the uppermost sheet and is raised as each new sheet is fed into position. This presser can be utilized to control the position of the table. The disadvantage of such a device when used in connection with a machine having a rather high delivery rate is that the motion of the presser foot becomes so rapid as to lead to undesinable effects, such as marks on the paper and other problems.

In view of the above consideration it is a primary object of the present invention to provide a'control for a table adapted to receive successive sheets of paper, or the like, in a stacked array, which control assures at all times that the topmost sheet will have the same position relative to the paper delivering mechanism within very close limits.

It is a further object of the present invention to provide a paper stacking table control which does not interfere with the feeding of sheets onto the stack. It is a further object of the present invention to provide a stacking table control which has a negligible effect upon the paper resting on the table.

Other objects and advantages will become apparent as the description proceeds.

Referring now to the drawing in which:

FIG. 1 is a view, with parts broken away, ferred form of the present invention;

FIG. 2 is a section on line 22 of FIG. 1; and

FIG. 3 is a section on line 33 of FIG. 2.

In the drawings, the delivery wheel 10 rotates in a direction, shown by the arrow, and permits the paper, which it is intended to deliver, to leave its working surface as the leading edge of the paper approaches the table 11. The table 11 may be provided with suitable pins, or the like, for assuring that the paper is properly positioned. Such pins are well known in the art and form no part of the present invention, and for clarity are thus not shown in the drawing. The table 11 is mounted by means of a flange fitting 12 on an elongated support 13. The elongated support 13 is connected to or forms part of a suitable piston and cylinder arrangement. In the shown form the element 13 takes the form of a piston rod working through a stufling box in the cylinder 14. A suitable piston 15 is connected to the rod 13 for movement within the cylinder in response to fluids admitted to one end or the other of the cylinder 14.

It can be seen that with the construction so far described all that is necessary in order that the structure carry out the functions intended for it that there be an accurate control of a fluid supplied to the top and bottom of the cylinder. Secured to the machine frame is a rod 16 which acts as a support for the control device about to be described. An elongated rectangular bar 17 is provided at one end with a suitable bearing surface 19 for engaging the bar 16. A mating piece 18 is secured to the portion 19 of the bar 17 in clamping relation to the bar 16 by any suitable mean such as bolts or the like. This arrangement permits bar 17 to he slid axially of the rod 16 and also provides a means whereby the angular relationship of the rectangular bar 17 to the table 11 may be changed for a reason which will become apparent as the description proceeds. Secured to the bar 17 is a base casting 19' which is provided with a slot for receiving the bar 17. A cooperating cap 20 is bolted to base casting 19 and in such a manner as to secure the base member 19 against sliding movement along the bar 17 while at the same time permitting ready adjustment upon loosening of the bolts.

Secured to the base member 19 there is provided a valve mechanism for controlling the pressure of fluid in the upper and lower portions of the cylinder 14. This valve consists essentially of a block 21 having an elongated bore therein to which bore transverse openings are provided for the inflow and efliux of fluid, normally air, as required to properly position the table 11. The flow of of a pre- 3 air to the cylinder is controlled by a small sliding valve 22. The position of the valve 22 is controlled in turn by a mechanism actuated by a finger resting upon the uppermost sheet of the pile of paper on the table 11. The valve 22 consists essentially of three cylindrical members 23, 24 and 25 closely fitting but freely slidable within the bore 26. These three cylindrical portions are connected by portions of reduced diameter 27 and 28. For the purpose of providing a supply of air to the top and bottom of the cylinder 14, a transverse bore 30 intersects the bore 26 and is provided at its outer end with a suitable connection for the supply of air or other compressed gas, as can be seen in the portion 24 of the valve 22 norm-ally closes the bore 30 when the valve is in its central position as shown. A transverse bore 31 also intersects the longitudinal bore 26 and is connected to the top of the cylinder 14. Similar transverse bore 32 also intersects the longitudinal bore 26 and is connected to or in communication with the bottom of the cylinder 14. Because of the reduced portions 27 and 28 in this sliding valve member,

upward movement of the valve 22 will result in communication between the lateral bore 30 and bore 32 .con nected to the bottom on the cylinder. Pressure at the bottom of the cylinder will thus be increased and the table 11 will rise conversely, downward motion of the valve member 22 will cause communication between the air supply 30 and the port '31 communicating with the top of the cylinder resulting in a lowering of the table 11.

It will be realized of course that the mere supply of air to one end of the cylinder or the other will not necessarily cause the piston to move and it is necessary to vent air from the opposite end from that to which air is supplied. For this purpose two additional transverse ports 33 and 34 are provided intersecting the longitudinal bore of the valve body. These bores or vents are placed in communication with corresponding cylinder portions upon motion of the valve 22 to permit motion of the piston 15 in the required direction under the influence of air being injected into the opposite end of the cylinder.

From what has been said so far it can be seen that the valve 22 is not required to resist or overcome any pressure differences of any substantial amount and the only pressures exerted on it are the transverse direction which may tend to increase frictional resistance to the movement of the valve 22. Even thiseffect can be minimized by proper proportioning of the various openings between the transverse ports and the longitudinal bore and by proper positioning of these bores to bring such total transverse forces to a minimum.

All that remains to be done is to provide a means responsive to the position of the uppermost sheet on the table 11 to cause motion of the valve 22 in appropriate direction. This has been done in the present invention by the use of an orifice which is constantly supplied with air at a substantially constant pressure so that restriction of the orifice will cause an increase in pressure behind the orifice. This increase of pressure is used to drive the valve body 22 in one direction. Decreasing the restriction of the orifice will cause a decrease in pressure therebehind and such decrease, as utilized in the present invention, permits motion of the valve body 22 in the opposite direction.

Referring to FIG. 2 longitudinal bore 26 is provided at one end with a body 36 having a relatively small perforation 37 along its axis. The space behind the body 36 is in communication with the compressed air supply in the port 30 by means of a longitudinal bore 38 extending from one end of the member 21 to the bore 30, which serves as a source of air under pressure. The outer end of the bore 38 is closed by means of screw 40 or the like. Transverse bore 30 extends through bore 38 to the space 42 behind the orifice.

A suitable means for making a restricted opening at this point comprises the threaded hollow fitting 43 which has a side opening in communication with the bore '38 and end opening in communication with the space 42. If desired, adjustment means may be provided rather than the fixed openings shown in the screw fitting 43.

For the purpose of detecting the surface of the paper piled on the table 11 a lever 50 may be pivoted to a portion of the base 19 by rneans of a screw 51. An upwardly extending undersurface 52 is provided to permit the delivery mechanism 10 to readily eject blanks under the element 50. It will be appreciated that the lever 50 should have a minimum weight commensurate with its functions and possibly should be counterbalanced to enable it to exert the correct force on the surface of the pile material on the table 11. Atrthe end opposite from the surface 52 lever 50 is provided with a flat portion 54 welded or otherwise secured to the lever proper. A strip of thin spring material 55 is secured to the flat portion 54 by means of a plate 56 and suitable fasteners such as screws. As can be seen this flexible material is so formed as to pass over the opening of the nozzle body 36. Movement of the element 55 toward and away from the opening in the orifice changes the pressure in the space behind the orifice and thus causes motion of the valve body 22 in the desired direction. In order to obtain a more accurate adjustment it is possible to utilize a thin lead spring 58 secured by a bracket 59 to the body 21 of the valve mechanism which overlies the opening on the orifice 36 and which is in turn overlaid by a movable spring 55. Motion of the spring 55 thus moves spring 58 to vary the flow through the orifice.

In order to provide a suitable force for positioning the valve when the conditions are such that no movement of the table is needed, a spring 60 may be provided within the body 21 in an extension of the longitudinal bore. Adjust-ment of such spring in order to obtain the correct tension of compression can be accomplished by rotating a suitable bolt 61 which can be adjusted by rotation, and locked in position by a lock nut 62.

The spring 60 is used to counterbalance a nozzle pressure which is always present within the space 42.

The operation of the device is stable when the table or top of the paper positions the lever 50 so that a nozzle pressure is developed within space 42 which is suflicient to overcome the force of spring 60 to move the valve 22 to its center position. Any error in the position of lever 50 will cause an unbalance of pressure in the piston 15 which will move the lever 50 to the position whereby a pressure balance is produced returning the valve to its centered position.

Although a preferred embodiment of the invention has been shown and described, the invention is not so limited and should only be defined by the following claims.

What I claim is:

1. A device for controlling the position of a sheet receiving table to maintain the top sheet of a stackthereon in a constant spatial relationship to a sheet delivering device comprising means responsive to fluid pressure for elevating and lowering said table, valve means connected to said pressure responsive means operative to move the table upon actuation, lever means for engaging the top sheet of the stack and movable therewith, said valve means including a control nozzle and means includingnozzle pressure control means responsive to movement of the lever means for controlling the flow of gas through said nozzle thereby to cause movement of said valve means into predetermined operational positions.

2. A device as claimed in claim 1, wherein said nozzle pressure control means comprises a closure member se-.

cured for movement with said lever means, said closure member at movement of said lever means in onedirection being adapted to restrict said nozzle whereby the pressure behind said nozzle increases, and at movement of said lever means in a direction opposite to said one direction, said closure member being adapted to move away from creases.

References Cited UNITED STATES PATENTS Peterson 271-88 X 5 Baker et a1. 271-62 Williams 271-88 X Bradshaw 271-62 X Weidenhammer 271-88 6 2,977,116 3/1961 Edminster 271-88 3,123,355 3/1964 Lessig 271-62 3,173,681 3/1965 David et a1 271-62 FOREIGN PATENTS 551,913 1/1958 Canada.

M. HENSON WOOD, JR., Primary Examiner. ALLEN N. KNOWLES, Examiner. 

1. A DEVICE FOR CONTROLLING THE POSITION OF A SHEET RECEIVING TABLE TO MAINTAIN THE TOP SHEET OF STACK THEREON IN A CONSTANT SPATIAL RELATIONSHIP TO A SHEET DELIVERING DEVICE COMPRISING MEANS RESPONSIVE TO FLUID PRESSURE FOR ELEVATING AND LOWERING SAID TABLE, VALVE MEANS CONNECTED TO SAID PRESSURE RESPONSIVE MEANS OPERATIVE TO MOVE THE TABLE UPON ACTUATION LEVER MEANS FOR ENGAGING THE TOP SHEET OF THE STACK AND MOVABLE THEREWITH, SAID VALVE MEANS INCLUDING A CONTROL NOZZLE AND MEANS INCLUDING NOZZLE PRESSURE CONTROL MEANS RESPONSIVE TO MOVEMENT 